Three ways to implement Fibonacci columns in JS

The following is the Javascript basics tutorial column to introduce the three methods of JS to realize the Fibonacci sequence number, I hope it will be helpful to friends in need! Three methods of implementing Fibonacci columns in JS How do you realize the Fibonacci series 1,1,2,3,5,8… f(n)=f(n-1) + f(n-2) Method 1: function f(n){ if(n == 1 || n == 0){ return 1; } return f(n-1) + f(n-2); } index.html Give two more solutions for comparison Method 2: function f(n ) { var arr = []; var value = null; function _f(n) { if (n == 1 || n == 0) { return 1; } if (arr[n]) return arr[n]; value = _f(n – 1) + _f(n – 2); arr[n] = value; return value; } return _f(n); } Method 2 Another simpler way is to use array storage Method 3: function fn(n) { var dp = new Array(n + 1); dp[0] = dp[1] = 1; for (let i = 2, length = dp.length; i <length; i++) { dp[i] = dp[i – 1] + dp[i – 2]; } return dp[n]; }